A231848 - OEIS

%I #12 Sep 12 2017 19:08:48

%S 1,2,3,4,5,6,7,8,9,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,

%T 95,100,150,200,250,300,350,400,450,500,550,500,550,600,650,700,750,

%U 800,850,900,950,1000,1500,2000,2500,3000,3500,4000,4500,5000,5500

%N A sequence of rounded numbers meaningful for entering values over several orders of magnitude in computer-human interfaces.

%C A slider in a user interface is often hard to represent when the range of numbers is large. This sequence produces a list of numbers that make it possible to select a meaningful value at all orders of magnitude.

%F n <= 9: n,

%F n > 9: (((n+8) mod 18)/2 + 1) * 10^(floor((n+8)/18)).

%t Table[If[n <= 9, n, (Mod[n + 8, 18]/2 + 1)*10^Floor[(n + 8)/18]], {n, 50}] (* _T. D. Noe_, Nov 27 2013 *)

%K nonn,easy

%O 1,2

%A _Lasse Klein_, Nov 14 2013